B&T Industries 4" Flush Cup 1913 Rail: flat back center-to-center hole spacing of 2.2 - 3.5" approx. BT17
B&T Industries 4" Flush Cup 1913 Rail: flat back center-to-center hole spacing of 2.2 - 3.5" approx. BT17, ThisAtlas4" rail will accommodate hole patterns with a center to center spacing of 2.2" - 3.5" with a flat back.